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August 18, 2008

Enhanced Oil Recovery Techniques Could Make a Difference

by Sam Savage

By Gillette, Becky

It sounds entirely unlikely: Could natural microbes in oil fields be fertilized in an enhanced oil recovery process that would allow twice as much oil to be recovered from fields previously considered "spent" than was originally produced?

With soaring fuel costs causing grave concern about the economy and even national security, being able to recover more oil from old oil fields could have huge implications. And a researcher at Mississippi State University, professor emeritus Dr. Lewis Brown, has proven that his microbial oil recovery method does work. A pilot project scheduled to be closed in 1998 is still producing.

"It is called incremental oil," Brown said. "It is oil you got out that you aren't supposed to get out. Two-thirds of all oil already discovered is still in the ground. Therefore, we have twice as much oil as has ever been produced. There is no cost in locating it. We just couldn't get it out in an economical way before. We've now developed a method to get a lot more of the oil out of the ground."

Step by step to the surface

Usually, when an oil well first starts to produce, the oil flows out because of the tremendous pressure of the earth over the reserve. Once that pressure is reduced, pumps are used to recover the oil. When the oil can no longer be pumped, secondary recovery is the next step. Water is pumped down into a well in the middle of an oil field, which pushes oil to other wells in the area. Another secondary recovery technique uses carbon dioxide in a similar manner.

Brown said after a while, when the water injection method starts declining in effectiveness, you may be getting only five barrels of oil along with 95 barrels of water.

"That gets uneconomic, so they shut the field down with two thirds of the oil still in the ground," Brown said. "What I do is feed the microbes present in the oil sands. The microbes have been there for millions of years, up to 250 million years, in a state of suspended animation. Oil consists of carbon and hydrogen. They don't have the nitrogen and phosphorus they need to grow so they go into a state of dormancy."

When you pump water in one well to force oil to come out of another well, the underground oil pathways get bigger and bigger until soon you are pumping water down one well and drawing it out of another. What Brown does is feed the microbes by adding nitrates and phosphates-the same nutrients used to fertilize crops - into the wells, and this resurrects the microbes.

"Now they begin to grow," Brown said. "They grow on the side of the holes partially blocking them and that forces the water to sweep other areas of the oil field so you get more oil out. The holes are not large, but little channels. Microbes grow on oil sands and block part of it so now the hole is not as big. The water has to go somewhere else."

Brown's method, called microbial permeability profile modification, only injects plant nutrients. Brown said by feeding only naturally occurring microbes in the oil-bearing formations, problems are avoided that can plug the wells.

Pilot well still producing

The technique was demonstrated with a $3.8-million grant from the U.S. Department of Energy working with a company based in Jackson in the North Blowhorn Creek oil field in Alabama.

The oil field was supposed to have been shut down as uneconomical in 1998. It is still producing today after recovering an estimated 400,000 to 600,000 extra barrels of oil.

With oil hovering at the $145 per barrel mark, Brown's cost per barrel is a real bargain at $1.32.

Brown is in the process of beginning a field trial in Mississippi with a company doing a carbon dioxide flood instead of a water flood with the intent of increasing the sweep efficiency of the carbon dioxide flood. That project is scheduled to start in August.

As would be expected, the techniques developed by the veteran microbiology professor are causing a great deal of excitement in the oil world. He is working with a company in England handling an oil field in Kuwait. Another company is planning to use the technique in Oman.

The availability of oil is considered important to national security. So Brown's discovery that successfully made it from the lab to the field could have huge implications for political and economic security.

Brown received a letter of commendation from then Secretary of Energy in the Clinton Administration, Bill Richardson (now governor of New Mexico).

"As he indicated, this helps the security of the country," Brown said. "The more oil we can get domestically lessons our dependence on foreign oil which is particularly important if we get into a conflict and can't import oil. It is of national importance to generate more oil in this country. That is what we are doing. I find it very exciting."